What Is… Reductionism in Psychiatry

Reductionism in psychiatry: mental illness = all biological or all psychosocial

In this series, I dig a little deeper into the meaning of psychology-related terms. This week’s term is reductionism.

Reductionism is the idea that complex theories or phenomena can be reduced down to other theories or phenomena. Essentially, the whole shebang can be boiled down to one thing that explains it all. It’s a philosophical concept that applies to a lot of different things, but I talk about it sometimes in blog posts, and I thought it would be good to take a look at what it actually means.

Types of reductionism

There are three broad types of reductionism:

  • Ontological: This is based on what kinds of things exist and what the relationships are between them. In psychiatry, ontological reductionism would be the idea that the physical brain is what exists, and the mind arises from the physical brain rather than being some separate type of entity (like a soul in a religious sense). This form of reductionism is quite commonly accepted within the psychiatric world.
  • Methodological: This involves selecting research methods based on ideas about ontology. In the case of mental illness, this could mean conducting research on the brain because of the belief that that’s how one is able to understand mental illness. That could mean missing the boat on other ways of investigating mental illness.
  • Epistemic: Epistemology is a fancy way of referring to what knowledge is and how we can know it. Epistemic reduction is the idea that knowledge about one thing can be understood based on knowledge about another thing. In the case of mental illness, that might mean assuming that knowing everything there is to know about dopamine signalling in the mesolimbic pathway can tell you everything there is to know about the experience of psychosis.

Reductionism and mental illness

Within the field of psychiatry, there have been some people who say that the experience of mental illness can be understood if only one fully understands the biological aspects, while others say that you can fully understand mental illness only by fully understanding the psychosocial factors that have shaped an individual’s experiences (for example, the Freudian psychodynamic perspective reduces experiences and behaviours down to instinctive drives). The former is associated with a biomedical model of mental illness, while the term emergentism is used for the belief that a phenomenon like mental illness doesn’t arise from physical properties.

Methodological reduction can refer to research strategies used to investigate mental illness, but it can also refer to treatment strategies. This can lead to practitioners focusing only on how different interventions influence the brain or only on interventions that target psychosocial aspects of an individual’s experience.

The problem with reductionist approaches is that they can cause people to lose sight of the bigger picture by getting fixated on particular kinds of details. Reducing a complex concept to a single issue that supposedly explains it all can go to different extremes, often in the form of a dichotomy (as in something is all A or all B, with no in the middle). These extremes are problematic, whether we’re talking about A or B.

Why should biological and psychosocial ways of understanding mental illness be mutually exclusive? Why can’t we have grey areas?

Moving away from reductionism

The biopsychosocial model, proposed by Dr. George Engel in the late 1970s, says that both physical characteristics and psychosocial factors contribute to illness. This is now pretty widely accepted and taught when it comes to mental illness.

Moving away from reductionism doesn’t mean that we need to accept all possibilities, including things that have been disproven. It also doesn’t mean that Occam’s razor, a heuristic (i.e. mental rule of thumb) that says that entities should not be multiplied beyond necessity, goes out the window entirely.

Sometimes things are multiple by necessity, as that’s simply what they are. Holism, the notion that the whole is greater than the sum of its parts, is essentially the opposite of reductionism. When it comes to mental illness, a holistic approach seems to make sense. As a side note, I don’t mean holistic in the sense of alternative health; I’m actually quite curious how that term got co-opted in that way.

There just don’t seem to be any simple explanations for mental illness, and it probably doesn’t do anyone much good to approach the matter as if that’s what we’re looking for. If a phenomenon is inherently complex, we shouldn’t pretend that it’s not.

Bring on the grey areas

What got me thinking recently about the concept of reductionism was watching videos of Jordan Peterson. He is reductionistic on the side of biology when it comes to sex/gender differences; he thinks the whole thing can be explained by the relevant biological factors. The people he criticizes as being radical leftists are reductionistic on the side of believing that social constructs fully explain the differences between males and females. Just because one side sees black and the other side sees white doesn’t mean there’s no grey, yet neither side seems inclined to acknowledge the existence of any grey (or the fact that they’re just opposite sides of the reductionistic coin).

I’m pro-grey. There are things that can be reduced to help people see the grey more clearly, but reducing to the point that you’re blinded to other shades really isn’t useful.

Does any of this make sense? What do you think of the usefulness of making room for grey rather than opting for reductionistic black or white?


The Psychology Corner: Insights into psychology and psychological tests

The Psychology Corner has an overview of terms covered in the What Is… series, along with a collection of scientifically validated psychological tests.

Ashley L. Peterson headshot

Ashley L. Peterson


Ashley is a former mental health nurse and pharmacist and the author of four books.

14 thoughts on “What Is… Reductionism in Psychiatry”

  1. I don’t care that Jordan Peterson has a PhD, the types of things he stands for are all out anti-intellectual. That’s the conservative right in America. Anti-intellectual. Doing more harm than good, and helping no one but themselves. So sad.

  2. I liked the pointing out that reductionism is a problem whether you fall on the black or the white side. That’s a true story people on the “right” side often seem to forget. Like you, I prefer holism, again in a non-granola sort of way.

    I will say though, that keeping an open mind when I see the name “Jordan Peterson” is a challenge. I find him triggering.

  3. I think mental health is one of the more important things not to be viewed as black and white, which I imagine can be quite harmful. I’m also not a fan of Jordan Peterson, I heard a recent interview with his daughter in which was referred to as a philosopher. Not a term I would use!

  4. Reductionism, as the basis of the biological psychiatry, and therefore the sources of the illness metaphor as the supposed scientific explanation of mental distress, is dangerous because it is wrong scientifically, because it locates the source of distress in the person rather than the society they live in.

    The British Psychological Society recently published a very detailed and comprehensive alternative explanation of this issue, called ‘The Power Threat Meaning Framework’, and it is available as a free download from their site.

    1. The way I see it, though, viewing the source of distress as entirely outside of a person is just as problematic as viewing it as being entirely inside the person. I believe that in most cases there’s an interplay of both. For some people, it might be more of one than the other, but I don’t think it makes sense to try to explain everyone’s illness experience through one specific lens.

      1. So we disagree. From my point of view, as the BPS PTMF explains in great detail, the evidence basis for the social milieu is far more substantial than individual characteristics – there are still no credible internal biomarkers for so-called ‘mental illness.’

        There is also a large and growing body of evidence for the social ontogeny of consciousness, which militates strongly against internal reductionist explanation.

        Also I cannot agree that the social milieu constitutes ‘one specific lens’, because it is so large and long-lasting – the sum of all a person’s social interactions throughout their life.

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